Hydraulic power distribution valve



Jan. 3, 1956 c. J. CLARK HYDRAULIC POWER DISTRIBUTION VALVE Filed Nov. 21, 1952 INVENTOR: CHARLES J. CLARK ATT'YS United States Patent HYDRAULIC POWER DISTRIBUTION VALVE Charles J. Clark, Oak Park, Ill.

Application November 21, 1952, Serial No. 321,831

2 Claims. (Cl. 137-621) The main objects of this invention are to provide an improved form of valve for controlling hydraulically operated mechanisms wherein the power is alternately reversed in direction, and wherein the activating liquid is supplied by a continuously operating pump with appropriate ducts for returning the operating fluid to a reservoir from the several places in which it has been used; and to provide a simple and inexpensive valve structure for the accomplishment of this purpose.

A specific embodiment of this invention is shown in the accompanying drawings in which:

Figure 1 is a scematic view partly sectional showing the relation of the valve to a hydraulic supply system, the valve being shown in its neutral position where power is cut oif from the driven mechanism but the pump is permitted to run.

Fig. 2, is a similar view of the valve mechanism alone showing its parts in position for directing the hydraulic liquid toward one side of the driven mechanism, and returning the fluid to the reservoir from the opposite side of the driven mechanism.

Fig. 3 is a similar view with the valve parts in position for reversing the flow of hydraulic fluid with respect to the driven mechanism.

Fig. 4 is a perspective view of an appropriate physical embodiment of the valve.

Fig. 5 is an enlarged longitudinal section of the valve casing taken on the plane of the axes of the bores and showing the relation of its pistons to each other.

In the form shown, the casing has two parallel cylindrical valve bores 11 and 12, each having a valve plunger longitudinally slidable therein and comprising a plurality of spaced pistons. The bores are open ended and the plungers have stems 13 and 13.1, which extend beyond both ends of the casing 10 and are there connected in fixed relation to each other by yokes 14 and 15. The yokes 14 and 15 also serve as limit stops for the longitudinal movement of the plungers. In the form shown, the operating mechanism for shifting the plungers comprises a lever 16 pivotally connected to the yoke 15 at 17 and to the casing 10 by a pair of links 18.

In the schematic diagram of Fig. l the valve is shown in relation to a hydraulic power system comprising a driven mechanism represented by a cylinder 19 and piston 20, a reservoir 21 and a pump 22. A system of piping provides for circulation of hydraulic liquid from the reservoir to the pump to the valve, which then distributes the supply of power alternately to either end of the cylinder 19, and at the same time directs a return flow of the exhausted liquid from the other end of the cylinder 19 back to the reservoir. The improved valve also has one plunger position wherein the supply of operating fluid is cut off from the cylinder 19 and is by-passed back to the reservoir, permitting the pump to operate continuously without interruption by stoppage of the driven mechanism.

To this end the valve bores 11 and 12 have a common inlet or supply port 23, which, in the form shown, leads first into the bore 11 and is connected by a branch passage 2,729,241 Patented J an. 3,1956

- 24 through the partition wall 25 to the bore 12. Each valve plunger comprises a stem carrying a series of spaced pistons spaced apart along the stem by spool shaped units which provide annular fluid passages. These spools and pistons are bored to fit the stem. In the neutral or middle position of the valve plungers in their reciprocatory travel along the bores, as shown in Figs. 1 and 5, the spindle 13 of the bore 11 has a spool 26 shaped to open communication between the ports 23 and 24, and the spindle 13.1 in bore 12 has a spool 27 shaped to open communication between the port 24 and the exhaust port 28. A fluid supply pipe 29 connects the pump 22 with the inlet port 23, and a return pipe 30 connects the outlet port 28 with the reservoir 21. Thus, when the lever 16 is at the middle point of its stroke as indicated in Fig. l, the operation of the pump 22 will circulate hydraulic fluid through the pipe 29, then through ports 23, 24 and 28 in the valve casing, and then through pipe 30 to the reservoir. The plunger in the bore 12 has pistons 31 and 32 at opposite ends of the spool 27 in position to cut off communication between the ports 24 and 28 when the plungers are at either end of their movement in the bores.

The bore 11 has power feed ports 33 and 34, equally spaced axially from the centrally located inlet port 23. The power feed port 33 is connected by pipe 35 with one end of the cylinder 19, and the power feed port 34 is connected by pipe 36 to the cylinder 19 at the opposite side of the piston 20. The bore 11 has a pair of exhaust ports 37 and 38 between the feed ports 33 and 34 and the respective ends of the casing 10. These exhaust ports are respectively connected by pipes 39.1 and 30.2 with return pipe 30. The ports 37, 33, 23, 34 and 38 in the form shown, are equally spaced apart along the axis of the bore 11, and the plunger stem 13 has mounted thereon two spools, 39 and 40, located beyond the ends of the spool 26 in such position that when the plungers are at either end of their axial movement, one of the spools 39 and 40 will connect the inlet port 23 with the adjacent power feed port 33 or 34, while the other spool will connect the other power feed port with the adjacent exhaust port, and vice-versa, as illustrated diagrammatically in Figs. 2 and 3. The plunger in bore 11 has piston members 41 and 42 beyond its spools, and these piston members and the spools are provided with suitable packings 43 that prevent leakage and cut oil communication between the ports at all points except where such communication is established by one of the spools.

As is well understood in respect to valves of this general class, the plunger structures are such that there is no unbalanced axial pressure tending to shift the plungers. Likewise lateral pressure upon the plungers is balanced at each port either by enlarging the bore of the casing in the vicinity of the ports, as indicated at 44 in Fig. 5, or by providing spool formations 26 and 45 in the plunger or by employing both of these expedients.

The operation of the device shown is as follows: When it is desired to deliver power to the driven mechanism for movement in one direction, as for example, to drive the piston 24) toward the left of Fig. 1, the operating lever 16 is thrown to the limit of its movement to the left as indicated in Fig. 2. This brings the spool 40 into position for connecting the supply port 23 with the feed port 34, to supply operating fluid to the cylinder 19, through the pipe 36. At the same time the spool 39 is brought into position for connecting the port 33 with the exhaust port 37, allowing the fluid in the left hand end of the cylinder 19 to escape through pipe 35 to port 33, and then through exhaust port 37 and pipes 30.1 and 30 to the reservoir. In this position of the valve mechanism, the piston 32 blocks the connection between port 23 and port When the lever 16 is in the middle position of its stroke amen as in-Fig. 1, the spools 3-9 and 40 are in the position shown. in. Fig. 5, and. there. is. a. clear. open. passageior. the fluid entering the supply port 23 to be by-passed through port 28 and pipe 30, to the reservoir, so that the pump can continue its operation while the mechanism represented by the. cylinder 1 9 is stationary.-

When the lever; 16 'is thrown to the right, as indicated in Fig. 3 to the limit of its movement, where the yoke 15 abuts against the end of the valve casing, then the piston 31. closes port 38, the spool 3 9-connects the ports 23' and 33. for delivering power to the left hand end of the cylinder 19 throughpipe 3S, and the right hand end of the cylinder is exhausted through pipe 36, port 34, spool 40, port 38, pipes 30.2 and 30 to the reservoir.

Although but one specific embodiment of this invention is herein shown and-described; it will he understood that numerous details of the construction shown may be altered or omitted without departing from the spirit of the invention as defined by the following claims.

1 claim:

1. A valve comprising a casing having two parallel bores, plungers in said bores connected together in fixed relation to each other for simultaneous longitudinal movement in either direction from a middle position in said bores, stop means to limit the stroke of said'plungers, one of said bores having five ports spaced apart longitudinally thereof, a passage connecting said bores for direct communication with the middle one of said five ports, the other said bore having an outlet port spaced laterally from said passage, the plunger in said other bore comprising a pair of pistons fixed thereon and spaced apart axially for establishing communication between said last named port and said passage when saidplungers are at mid-stroke and to cut oif such communication when said plungers are at either end of their stroke, and the plunger in said one bore comprising three pistons spaced apart axially for establishing communication selectively between the middle one of said five ports and the next adjacent port only at either side of said middle one while establishing communication between the two ports on the other side 4. of said middle one and simultaneously cutting off communication between the. ports. on the. opposite side of said middle one, the central one; of said three pistons having a peripheral groove normally establishing communication between the middle port and said passage when the respective plunger is in mid-stroke position.

2. A valve comprising a casing having two parallel bores, plungers in said bores connected together in fixed relation toeach other for, simultaneous, longitudinalmovement in either direction from a middle position in said bore, means for limiting; the stroke of said plungers in either direction, one of said bores having five ports spaced apart longitudinally thereof and opening outwardly from said casing, a passageirr said casing for connecting said bores and having direct communication with the middle one of said five ports, the other of said bores having an outlet port spaced laterally away from said passage in the axial direction of said bore, the plunger in said other bore comprising a pair of pistons fixedthereon and-spaced apart axially for establishing communication between said last named port and said passage when said plungers are at mid-stroke position and to cut off said communication when saidplungers'are at either end of their stroke, and the plunger insaid one bore comprising three pistons spaced apart axially for establishing communication sclectively between the middle one of said five ports and the next adjacent port only at either side of said middle one port while establishingcommunication between the two ports on the other side of saidmiddle one port, and simultaneously cutting off communication between the ports on the oppositeside of said-middle one port.

References Cited in the file of this patent UNITED S ATES PATENTS 2,342,770 Temple Feb. 29, 1944 2,489,435 Robinson Nov. 29, 1949 2500,758 'Kupiec Mar. 14, 1950 2,613,650 Mott Oct. 14, 1952 2,643,674 Lapsley June 30, 1953 

